ElpiAuto275/60R20 vs 315/60R20
315/60R20 is 1.89″ (48 mm) taller than 275/60R20, a 5.7% difference in overall diameter — outside the ±3% band, so expect the speedometer to drift and check for rubbing before fitting.
| Measurement | 275/60R20 | 315/60R20 | Difference | % |
|---|---|---|---|---|
| Overall diameter | 32.99″ | 34.88″ | +1.89″ | +5.7% |
| Section width | 10.83″ | 12.40″ | +1.57″ | +14.5% |
| Sidewall height | 6.50″ | 7.44″ | +0.94″ | +14.5% |
| Circumference | 103.65″ | 109.58″ | +5.94″ | +5.7% |
| Revs per mile | 611.3 | 578.2 | −33.1 | −5.4% |
| Revs per km | 379.8 | 359.3 | −20.6 | −5.4% |
Speedometer: with 275/60R20 as the original, 315/60R20 makes an indicated 60 mph really about 63.4 mph, and the axle sits ~0.94″ higher.
Reading this comparison
The overall diameter is what matters here: 315/60R20 is the taller tire. It sets ride height, gearing and how far the tire travels per revolution — which is what the speedometer and odometer count. Width and sidewall change fit and feel (a wider tire needs a wider wheel and more clearance; a shorter sidewall sharpens steering) but not the gearing.
Figures are geometric estimates from the size codes; real moulded tires vary by brand by 1–3%. Confirm load rating, wheel width and physical clearance on your vehicle before fitting. To compare any other two sizes, use the tire size comparison tool; to decode one size and see what else fits its wheel, the tire size calculator.